The synthesis of potassium 3-sulfopropyl methacrylate (SPMA) homopolymers and amphiphilic block copolymers with methyl methacrylate (MMA) by ATRP in water/DMF mixed solvent at 20 °C using a Cu/bipyridine catalyst and halogen exchange is described. SPMA homopolymerization in pure water was poorly controlled even when 200% of Cu(II)Cl 2 with respect to Cu(I)Cl was added, leading to a relatively high polydispersity (1.38). In water:DMF 50:50 (v/v), addition of at least 60% of Cu(II)Cl2 with respect to Cu(I)Cl allowed to obtain a good control of the polymerization. Linear kinetic plots up to very high conversion were observed and the final polydispersities were relatively low (1.15-1.25). Good self-blocking efficiencies were demonstrated by chain extension experiments even when the first block conversion before the addition of the second feed was very high (>90%). Amphiphilic block copolymers with MMA (number-average degree of polymerization X n,SPMA ) 50, Xn,MMA ) 25) were directly prepared in water:DMF 40:60 (v/v) without using protecting group chemistry or post-polymerization derivatization. The first-order kinetic plot for MMA polymerization was linear up to 96% conversion. Two block copolymers with the same composition, p(SPMA 50-b-MMA25)1pot and p(SPMA50-b-MMA25)2pot, were prepared with "onepot" and "two-pot" procedures. p(SPMA50-b-MMA25)2pot prepared using a purified pSPMA macroinitiator for MMA polymerization gave well-defined core-shell spherical micelles with an average hydrodynamic radius of about 14 nm determined by dynamic light scattering (DLS) measurements. p(SPMA50-b-MMA25)1pot prepared using the sequential monomer addition gave large micellar clusters (more than 100 nm) in addition to simple but smaller micelles. A tentative explanation to the presence of the larger aggregates was given.
Background Avian infectious bronchitis (IB) is a disease that can result in huge economic losses in the poultry industry. The high level of mutations of the IB virus (IBV) leads to the emergence of new serotypes and genotypes, and limits the efficacy of routine prevention. Medicinal plants, or substances derived from them, are being tested as options in the prevention of infectious diseases such as IB in many countries. The objective of this study was to investigate extracts of 15 selected medicinal plants for anti-IBV activity. Results Extracts of S. montana , O. vulgare , M. piperita , M. officinalis , T. vulgaris , H. officinalis , S. officinalis and D. canadense showed anti-IBV activity prior to and during infection, while S. montana showed activity prior to and after infection. M. piperita , O. vulgare and T. vulgaris extracts had > 60 SI. In further studies no virus plaques (plaque reduction rate 100%) or cytopathogenic effect (decrease of TCID 50 from 2.0 to 5.0 log 10 ) were detected after IBV treatment with extracts of M. piperita , D. canadense and T. vulgaris at concentrations of extracts ≥0.25 cytotoxic concentration (CC 50 ) ( P < 0.05). Both PFU number and TCID 50 increased after the use of M. piperita , D. canadense , T. vulgaris and M. officinalis extracts, the concentrations of which were 0.125 CC 50 and 0.25 CC 50 ( P < 0.05). Real-time PCR detected IBV RNA after treatment with all plant extracts using concentrations of 1:2 CC 50 , 1:4 CC 50 and 1:8 CC 50 . Delta cycle threshold (Ct) values decreased significantly comparing Ct values of 1:2 CC 50 and 1:8 CC 50 dilutions ( P < 0.05). Conclusions Many extracts of plants acted against IBV prior to and during infection, but the most effective were those of M. piperita , T. vulgaris and D. canadense .
Machine learning methods identify antiviral phytochemicals using CART decision trees.
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